Disable Placement editing for part design transformation features

src/Mod/PartDesign/App/FeatureTransformed.cpp

@@ -55,6 +55,16 @@ Transformed::Transformed() : rejected(0)
     Originals.setSize(0);
 }
 
+void Transformed::onChanged(const App::Property* prop)
+{
+    if (prop == &Originals) {
+        // if attached then mark it as read-only
+        this->Placement.StatusBits.set(2, Originals.getSize() != 0);
+    }
+
+    PartDesign::Feature::onChanged(prop);
+}
+
 void Transformed::positionBySupport(void)
 {
     Part::Feature *support = static_cast<Part::Feature*>(getSupportObject());

src/Mod/PartDesign/App/FeatureTransformed.h

@@ -78,6 +78,9 @@ public:
       */
     const std::list<gp_Trsf> getRejectedTransformations(void) { return rejected; }
 
+protected:
+    void onChanged(const App::Property* prop);
+
 protected:
     std::list<gp_Trsf> rejected;
 };